The present invention relates in general to remote controlling and more particularly concerns novel apparatus and techniques for using telephone lines and terminals for temperature control to provide a convenient meand for controlling and/or monitoring conditions, such as temperature, at a remote location. The apparatus is reliable, relatively inexpensive and consumes relatively little power.
An important aspect of national energy policy is energy conservation. To this end it is desirable to minimize the use of energy for maintaining a desired temperature in unoccupied locations. Thus, clocked thermostats have been used for many years to change the temperature setting in a particular area at predetermined times each day corresponding to the times when the nature of the occupancy of the temperature-controlled environment changes. A disadvantage of this arrangement is that these changes not infrequently occur at irregular times. One approach is to change the thermostat each time the environment becomes occupied and unoccupied. A practical disadvantage of this approach is that the unoccupied temperature differs from the occupied temperature by an increment less than necessary because of the discomfort experienced while restoring the temperature to the occupied value.
Accordingly, it is an important object of this invention to provide improved methods and means for remote controlling.
It is a further object of the invention to achieve the preceding object with apparatus that is convenient to use, reliable, relatively inexpensive, dissipates relatively little power and may be connected safely and relatively easily.
It is a further object of the invention to achieve one or more of the preceding objects with apparatus that uses energy available from thermostat terminals to which it is connected.
It is a further object of the invention to achieve one or more of the preceding objects while receiving control signals over a telephone line and signalling the controller of availability for receiving a control signal and acknowledging receipt of it.
It is a further object of the invention to achieve one or more of the preceding objects while providing to the remote location an indication of a potentially unsatisfactory condition, such as a temperature that is too low.
It is a further object of the invention to achieve one or more of the preceding objects with a process that is relatively simple to implement by an unskilled controller.
It is still a further object of the invention to enable local disablement and remote enablement of a temperature control system.